--- /dev/null
+/*
+ * rtc-mrst.c: Driver for Moorestown virtual RTC
+ *
+ * (C) Copyright 2009 Intel Corporation
+ * Author: Jacob Pan (jacob.jun.pan@intel.com)
+ * Feng Tang (feng.tang@intel.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ *
+ * Note:
+ * VRTC is emulated by system controller firmware, the real HW
+ * RTC is located in the PMIC device. SCU FW shadows PMIC RTC
+ * in a memory mapped IO space that is visible to the host IA
+ * processor.
+ *
+ * This driver is based upon drivers/rtc/rtc-cmos.c
+ */
+
+/*
+ * Note:
+ * * vRTC only supports binary mode and 24H mode
+ * * vRTC only support PIE and AIE, no UIE, and its PIE only happens
+ * at 23:59:59pm everyday, no support for adjustable frequency
+ * * Alarm function is also limited to hr/min/sec.
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sfi.h>
+
+#include <asm-generic/rtc.h>
+#include <asm/intel_scu_ipc.h>
+#include <asm/intel-mid.h>
+#include <asm/intel_mid_vrtc.h>
+
+struct mrst_rtc {
+ struct rtc_device *rtc;
+ struct device *dev;
+ int irq;
+ struct resource *iomem;
+
+ u8 enabled_wake;
+ u8 suspend_ctrl;
+};
+
+static const char driver_name[] = "rtc_mrst";
+
+#define RTC_IRQMASK (RTC_PF | RTC_AF)
+
+static inline int is_intr(u8 rtc_intr)
+{
+ if (!(rtc_intr & RTC_IRQF))
+ return 0;
+ return rtc_intr & RTC_IRQMASK;
+}
+
+static inline unsigned char vrtc_is_updating(void)
+{
+ unsigned char uip;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+ uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ return uip;
+}
+
+/*
+ * rtc_time's year contains the increment over 1900, but vRTC's YEAR
+ * register can't be programmed to value larger than 0x64, so vRTC
+ * driver chose to use 1972 (1970 is UNIX time start point) as the base,
+ * and does the translation at read/write time.
+ *
+ * Why not just use 1970 as the offset? it's because using 1972 will
+ * make it consistent in leap year setting for both vrtc and low-level
+ * physical rtc devices. Then why not use 1960 as the offset? If we use
+ * 1960, for a device's first use, its YEAR register is 0 and the system
+ * year will be parsed as 1960 which is not a valid UNIX time and will
+ * cause many applications to fail mysteriously.
+ */
+static int mrst_read_time(struct device *dev, struct rtc_time *time)
+{
+ unsigned long flags;
+
+ if (vrtc_is_updating())
+ mdelay(20);
+
+ spin_lock_irqsave(&rtc_lock, flags);
+ time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
+ time->tm_min = vrtc_cmos_read(RTC_MINUTES);
+ time->tm_hour = vrtc_cmos_read(RTC_HOURS);
+ time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
+ time->tm_mon = vrtc_cmos_read(RTC_MONTH);
+ time->tm_year = vrtc_cmos_read(RTC_YEAR);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+
+ /* Adjust for the 1972/1900 */
+ time->tm_year += 72;
+ time->tm_mon--;
+ return rtc_valid_tm(time);
+}
+
+static int mrst_set_time(struct device *dev, struct rtc_time *time)
+{
+ int ret;
+ unsigned long flags;
+ unsigned char mon, day, hrs, min, sec;
+ unsigned int yrs;
+
+ yrs = time->tm_year;
+ mon = time->tm_mon + 1; /* tm_mon starts at zero */
+ day = time->tm_mday;
+ hrs = time->tm_hour;
+ min = time->tm_min;
+ sec = time->tm_sec;
+
+ if (yrs < 72 || yrs > 138)
+ return -EINVAL;
+ yrs -= 72;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+
+ vrtc_cmos_write(yrs, RTC_YEAR);
+ vrtc_cmos_write(mon, RTC_MONTH);
+ vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
+ vrtc_cmos_write(hrs, RTC_HOURS);
+ vrtc_cmos_write(min, RTC_MINUTES);
+ vrtc_cmos_write(sec, RTC_SECONDS);
+
+ spin_unlock_irqrestore(&rtc_lock, flags);
+
+ ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
+ return ret;
+}
+
+static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct mrst_rtc *mrst = dev_get_drvdata(dev);
+ unsigned char rtc_control;
+
+ if (mrst->irq <= 0)
+ return -EIO;
+
+ /* Basic alarms only support hour, minute, and seconds fields.
+ * Some also support day and month, for alarms up to a year in
+ * the future.
+ */
+ t->time.tm_mday = -1;
+ t->time.tm_mon = -1;
+ t->time.tm_year = -1;
+
+ /* vRTC only supports binary mode */
+ spin_lock_irq(&rtc_lock);
+ t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
+ t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
+ t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
+
+ rtc_control = vrtc_cmos_read(RTC_CONTROL);
+ spin_unlock_irq(&rtc_lock);
+
+ t->enabled = !!(rtc_control & RTC_AIE);
+ t->pending = 0;
+
+ return 0;
+}
+
+static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
+{
+ unsigned char rtc_intr;
+
+ /*
+ * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
+ * allegedly some older rtcs need that to handle irqs properly
+ */
+ rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
+ rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
+ if (is_intr(rtc_intr))
+ rtc_update_irq(mrst->rtc, 1, rtc_intr);
+}
+
+static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
+{
+ unsigned char rtc_control;
+
+ /*
+ * Flush any pending IRQ status, notably for update irqs,
+ * before we enable new IRQs
+ */
+ rtc_control = vrtc_cmos_read(RTC_CONTROL);
+ mrst_checkintr(mrst, rtc_control);
+
+ rtc_control |= mask;
+ vrtc_cmos_write(rtc_control, RTC_CONTROL);
+
+ mrst_checkintr(mrst, rtc_control);
+}
+
+static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
+{
+ unsigned char rtc_control;
+
+ rtc_control = vrtc_cmos_read(RTC_CONTROL);
+ rtc_control &= ~mask;
+ vrtc_cmos_write(rtc_control, RTC_CONTROL);
+ mrst_checkintr(mrst, rtc_control);
+}
+
+static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct mrst_rtc *mrst = dev_get_drvdata(dev);
+ unsigned char hrs, min, sec;
+ int ret = 0;
+
+ if (!mrst->irq)
+ return -EIO;
+
+ hrs = t->time.tm_hour;
+ min = t->time.tm_min;
+ sec = t->time.tm_sec;
+
+ spin_lock_irq(&rtc_lock);
+ /* Next rtc irq must not be from previous alarm setting */
+ mrst_irq_disable(mrst, RTC_AIE);
+
+ /* Update alarm */
+ vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
+ vrtc_cmos_write(min, RTC_MINUTES_ALARM);
+ vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
+
+ spin_unlock_irq(&rtc_lock);
+
+ ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
+ if (ret)
+ return ret;
+
+ spin_lock_irq(&rtc_lock);
+ if (t->enabled)
+ mrst_irq_enable(mrst, RTC_AIE);
+
+ spin_unlock_irq(&rtc_lock);
+
+ return 0;
+}
+
+/* Currently, the vRTC doesn't support UIE ON/OFF */
+static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct mrst_rtc *mrst = dev_get_drvdata(dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+ if (enabled)
+ mrst_irq_enable(mrst, RTC_AIE);
+ else
+ mrst_irq_disable(mrst, RTC_AIE);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ return 0;
+}
+
+
+#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
+
+static int mrst_procfs(struct device *dev, struct seq_file *seq)
+{
+ unsigned char rtc_control, valid;
+
+ spin_lock_irq(&rtc_lock);
+ rtc_control = vrtc_cmos_read(RTC_CONTROL);
+ valid = vrtc_cmos_read(RTC_VALID);
+ spin_unlock_irq(&rtc_lock);
+
+ seq_printf(seq,
+ "periodic_IRQ\t: %s\n"
+ "alarm\t\t: %s\n"
+ "BCD\t\t: no\n"
+ "periodic_freq\t: daily (not adjustable)\n",
+ (rtc_control & RTC_PIE) ? "on" : "off",
+ (rtc_control & RTC_AIE) ? "on" : "off");
+
+ return 0;
+}
+
+#else
+#define mrst_procfs NULL
+#endif
+
+static const struct rtc_class_ops mrst_rtc_ops = {
+ .read_time = mrst_read_time,
+ .set_time = mrst_set_time,
+ .read_alarm = mrst_read_alarm,
+ .set_alarm = mrst_set_alarm,
+ .proc = mrst_procfs,
+ .alarm_irq_enable = mrst_rtc_alarm_irq_enable,
+};
+
+static struct mrst_rtc mrst_rtc;
+
+/*
+ * When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
+ * Reg B, so no need for this driver to clear it
+ */
+static irqreturn_t mrst_rtc_irq(int irq, void *p)
+{
+ u8 irqstat;
+
+ spin_lock(&rtc_lock);
+ /* This read will clear all IRQ flags inside Reg C */
+ irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
+ spin_unlock(&rtc_lock);
+
+ irqstat &= RTC_IRQMASK | RTC_IRQF;
+ if (is_intr(irqstat)) {
+ rtc_update_irq(p, 1, irqstat);
+ return IRQ_HANDLED;
+ }
+ return IRQ_NONE;
+}
+
+static int vrtc_mrst_do_probe(struct device *dev, struct resource *iomem,
+ int rtc_irq)
+{
+ int retval = 0;
+ unsigned char rtc_control;
+
+ /* There can be only one ... */
+ if (mrst_rtc.dev)
+ return -EBUSY;
+
+ if (!iomem)
+ return -ENODEV;
+
+ iomem = request_mem_region(iomem->start, resource_size(iomem),
+ driver_name);
+ if (!iomem) {
+ dev_dbg(dev, "i/o mem already in use.\n");
+ return -EBUSY;
+ }
+
+ mrst_rtc.irq = rtc_irq;
+ mrst_rtc.iomem = iomem;
+ mrst_rtc.dev = dev;
+ dev_set_drvdata(dev, &mrst_rtc);
+
+ mrst_rtc.rtc = rtc_device_register(driver_name, dev,
+ &mrst_rtc_ops, THIS_MODULE);
+ if (IS_ERR(mrst_rtc.rtc)) {
+ retval = PTR_ERR(mrst_rtc.rtc);
+ goto cleanup0;
+ }
+
+ rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
+
+ spin_lock_irq(&rtc_lock);
+ mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
+ rtc_control = vrtc_cmos_read(RTC_CONTROL);
+ spin_unlock_irq(&rtc_lock);
+
+ if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
+ dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
+
+ if (rtc_irq) {
+ retval = request_irq(rtc_irq, mrst_rtc_irq,
+ 0, dev_name(&mrst_rtc.rtc->dev),
+ mrst_rtc.rtc);
+ if (retval < 0) {
+ dev_dbg(dev, "IRQ %d is already in use, err %d\n",
+ rtc_irq, retval);
+ goto cleanup1;
+ }
+ }
+ dev_dbg(dev, "initialised\n");
+ return 0;
+
+cleanup1:
+ rtc_device_unregister(mrst_rtc.rtc);
+cleanup0:
+ mrst_rtc.dev = NULL;
+ release_mem_region(iomem->start, resource_size(iomem));
+ dev_err(dev, "rtc-mrst: unable to initialise\n");
+ return retval;
+}
+
+static void rtc_mrst_do_shutdown(void)
+{
+ spin_lock_irq(&rtc_lock);
+ mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
+ spin_unlock_irq(&rtc_lock);
+}
+
+static void rtc_mrst_do_remove(struct device *dev)
+{
+ struct mrst_rtc *mrst = dev_get_drvdata(dev);
+ struct resource *iomem;
+
+ rtc_mrst_do_shutdown();
+
+ if (mrst->irq)
+ free_irq(mrst->irq, mrst->rtc);
+
+ rtc_device_unregister(mrst->rtc);
+ mrst->rtc = NULL;
+
+ iomem = mrst->iomem;
+ release_mem_region(iomem->start, resource_size(iomem));
+ mrst->iomem = NULL;
+
+ mrst->dev = NULL;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mrst_suspend(struct device *dev)
+{
+ struct mrst_rtc *mrst = dev_get_drvdata(dev);
+ unsigned char tmp;
+
+ /* Only the alarm might be a wakeup event source */
+ spin_lock_irq(&rtc_lock);
+ mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
+ if (tmp & (RTC_PIE | RTC_AIE)) {
+ unsigned char mask;
+
+ if (device_may_wakeup(dev))
+ mask = RTC_IRQMASK & ~RTC_AIE;
+ else
+ mask = RTC_IRQMASK;
+ tmp &= ~mask;
+ vrtc_cmos_write(tmp, RTC_CONTROL);
+
+ mrst_checkintr(mrst, tmp);
+ }
+ spin_unlock_irq(&rtc_lock);
+
+ if (tmp & RTC_AIE) {
+ mrst->enabled_wake = 1;
+ enable_irq_wake(mrst->irq);
+ }
+
+ dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
+ (tmp & RTC_AIE) ? ", alarm may wake" : "",
+ tmp);
+
+ return 0;
+}
+
+/*
+ * We want RTC alarms to wake us from the deep power saving state
+ */
+static inline int mrst_poweroff(struct device *dev)
+{
+ return mrst_suspend(dev);
+}
+
+static int mrst_resume(struct device *dev)
+{
+ struct mrst_rtc *mrst = dev_get_drvdata(dev);
+ unsigned char tmp = mrst->suspend_ctrl;
+
+ /* Re-enable any irqs previously active */
+ if (tmp & RTC_IRQMASK) {
+ unsigned char mask;
+
+ if (mrst->enabled_wake) {
+ disable_irq_wake(mrst->irq);
+ mrst->enabled_wake = 0;
+ }
+
+ spin_lock_irq(&rtc_lock);
+ do {
+ vrtc_cmos_write(tmp, RTC_CONTROL);
+
+ mask = vrtc_cmos_read(RTC_INTR_FLAGS);
+ mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
+ if (!is_intr(mask))
+ break;
+
+ rtc_update_irq(mrst->rtc, 1, mask);
+ tmp &= ~RTC_AIE;
+ } while (mask & RTC_AIE);
+ spin_unlock_irq(&rtc_lock);
+ }
+
+ dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(mrst_pm_ops, mrst_suspend, mrst_resume);
+#define MRST_PM_OPS (&mrst_pm_ops)
+
+#else
+#define MRST_PM_OPS NULL
+
+static inline int mrst_poweroff(struct device *dev)
+{
+ return -ENOSYS;
+}
+
+#endif
+
+static int vrtc_mrst_platform_probe(struct platform_device *pdev)
+{
+ return vrtc_mrst_do_probe(&pdev->dev,
+ platform_get_resource(pdev, IORESOURCE_MEM, 0),
+ platform_get_irq(pdev, 0));
+}
+
+static int vrtc_mrst_platform_remove(struct platform_device *pdev)
+{
+ rtc_mrst_do_remove(&pdev->dev);
+ return 0;
+}
+
+static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
+{
+ if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
+ return;
+
+ rtc_mrst_do_shutdown();
+}
+
+MODULE_ALIAS("platform:vrtc_mrst");
+
+static struct platform_driver vrtc_mrst_platform_driver = {
+ .probe = vrtc_mrst_platform_probe,
+ .remove = vrtc_mrst_platform_remove,
+ .shutdown = vrtc_mrst_platform_shutdown,
+ .driver = {
+ .name = driver_name,
+ .pm = MRST_PM_OPS,
+ }
+};
+
+module_platform_driver(vrtc_mrst_platform_driver);
+
+MODULE_AUTHOR("Jacob Pan; Feng Tang");
+MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff